Hydraulic pumps, hydraulic motor-pumps and hydraulic motors are used in many industrial and household applications and may, under certain conditions, also be used as a means for transmitting power between the heat or electric engine of motor vehicles and the wheels of said vehicles. Various industrial and household applications could thus benefit greatly from a hydraulic motor-pump offering a high output at a moderate cost. It is nevertheless in the field of automobile propulsion that the positive environmental, energy and economic impact of such a hydraulic motor-pump would be the most obvious.
The large majority of motor vehicles driving throughout the world are propelled by reciprocating internal combustion heat engines operating primarily with oil-based fuels. For environmental, energy and economic reasons, reducing motor vehicle fuel consumption and the associated carbon dioxide emissions is a priority in most countries across the globe. Consequently, reciprocating internal combustion motor vehicle engines are subject to constant improvements to increase their output, in particular during everyday use.
Progress is not, however, limited to the heat engine itself: reducing the weight of motor vehicles, their aerodynamic drag and the rolling resistance of their tires also contributes to reducing the per-kilometer fuel consumption of said vehicles, by reducing the work their heat engines must supply to propel them. The use of onboard equipment with a high energy output also contributes to reducing the fuel consumption of motor vehicles, whether that equipment is dedicated to air conditioning for the passenger compartment, power steering, lighting, or information and communication.
Aside from the heat engine itself, at least four other strategies allow a noticeable improvement of the energy output of a motor vehicle:                Reducing friction losses produced by the members that transmit the mechanical work produced by the heat engine of said vehicle to its wheels;        Continuously optimizing the ratio of the transmission connecting said heat engine to the drive wheels of said vehicle such that said engine always works as close as possible to its operating point offering the best energy output;        Temporarily storing all or part of the mechanical work produced by the heat engine when its output is high, said work then being recovered so as to move the motor vehicle in the power ranges where the output of said engine is ordinarily low, so as to avoid using said engine in those ranges;        Recovering the largest possible portion of the kinetic energy of the motor vehicle during braking or deceleration thereof by replacing, as much as possible, the use of friction brakes, which dissipate said energy as a pure loss in the form of heat, by storing said energy in a form that can be reused in the reacceleration phase of said vehicle, the storage device for said energy having to offer the best possible output both in terms of storage and recovery, and having to have a storage and recovery power such that the greatest amount of kinetic energy of the vehicle can be recovered, then released.        
These four strategies are found alone or in combination in various types of transmissions that can be combined with various heat-electric, heat-pneumatic or heat-hydraulic hybrid devices, each configuration involving a compromise between various advantages and drawbacks, without any being fully satisfactory in practice.
At least two types of transmission are used in the context of motor vehicle propulsion: discrete ratio transmissions based on cluster gears, and continuously variable transmissions primarily based on belts, rollers or variable displacement hydraulic motor-pumps. Discrete ratio transmissions may be controlled manually or automatically, whereas continuously variable transmissions are generally controlled automatically.
The traditional gear transmissions have a high output, since the work that they transmit goes through smaller number of pairs of involute pinions. Furthermore, said transmissions are coupled with the heat engine using a dry disc clutch that only dissipates the energy during gear shifting, and in a small quantity. These transmissions are generally actuated by the driver, who selects the ratios thereof manually, at his own discretion. Said gear transmissions are known as “manual transmissions”. They still make up the majority of automobile production worldwide, since they offer the best mechanical output of all transmissions combined and are inexpensive to produce.
It is possible to optimize the use of the transmission ratios of traditional transmissions using a maximum output or maximum power criterion of the heat engine. This may be done by allowing software run by a microprocessor to choose the engaged ratio. In that case, an automaton replaces the driver, whose clutch pedal and gear shifter are replaced by electromechanical, electro-hydraulic or electro-pneumatic actuators acting directly on the clutch and the selection ranges of the transmission ratios. These “automated manual transmissions” offer both maximum mechanical output and good optimization of the operating points of the engine.
The main drawback of this configuration is relative slowness in shifting gears, which results—for the vehicle's driver—in an unpleasant sensation of loss of continuity in the transmission of the power. This problem is greatly attenuated, or even practically eliminated, if quick actuators are used, which cooperate with synchro rings that are also quick. The problem with the latter solutions is their cost, which limits them to transmissions for high-end and high-performance vehicles.
It is possible to benefit simultaneously from the high mechanical output of a robotic manual transmission and a rapid transition of transmission ratios by interlocking two transmissions in one another in the same casing. According to this configuration, the first transmission includes the even ratios, while the second includes the odd ratios. These so-called “dual-clutch transmissions” provide excellent transmission continuity of the power during gear shifting, since the ratio that follows the current ratio is pre-engaged. Thus, shifting up or down alternately calls on the clutch corresponding to the first transmission, then that corresponding to the second transmission, the two clutches never being engaged at the same time. However, dual-clutch transmissions remain heavier, more expensive and bulkier than traditional manual transmissions.
A large portion of the worldwide automobile market is equipped with so-called “automatic transmissions”. These transmissions, primarily marketed in North America, are generally connected to the heat engine using a hydraulic coupler or a hyperkinetic converter also called “torque converter”. As an alternative to the torque converter, said transmissions may be connected to the heat engine using a traditional automated dry or oil bath clutch. The automatic transmissions integrate a series of planetary gear sets whereof the rotation of the rings can be blocked by brakes, said rings thus blocked then transmitting the torque produced by the heat engine to the wheels of the vehicle. Automatic transmissions have the advantage of excellent progressivity in the transition of the ratios and good continuity of the power transmission. However, their output remains mediocre, since they involve considerable energy losses, whether due to the torque converter, any “lock-up” clutch, ratio selection clutches, and the various pump(s) and actuators that they include.
Another family of transmissions is called “continuously variable transmissions” (CVT). Continuously variable transmissions offer infinite ratios between two extreme ratios and generally transmit the work produced by the heat engine to the wheels of the vehicle via the friction between a trapezoidal belt and conical flank pulleys, or via the friction between the rollers of different shapes as found in the “toroidal” transmission produced by the company “Torotrak©” or the “Extroid©” transmission produced by the company “Nissan©”. While the smallest transmission ratio of said transmission is non-zero, it is ordinarily necessary to attach a clutch or torque converter to it placed between the heat engine and said transmission to start the vehicle. Unless they are extremely, or even excessively expensive to produce, continuously variable transmissions generally have a lower mechanical output than that of manual transmissions with involute gear pairs. However, said transmissions offering complete transmission continuity and infinite transmission ratios, they allow the heat engine to operate as close as possible to its optimal output in an ordinary driving situation of the vehicle, or at its maximum peak power when the driver pushes the vehicle to obtain a maximal acceleration or speed.
Hydraulic continuously variable transmissions also exist comprising at least one transmitting variable displacement or fixed displacement hydraulic pump and at least one receiving variable displacement or fixed displacement hydraulic motor-pump, the transmitting pump or at least the or said motor-pumps having to be with variable displacement. The transmitting pumps and/or receiving motor-pumps used are generally based on axial pistons or on an internal or external gear pair system.
The ratio between the displacement of the transmitting pump and that of the receiving hydraulic motor-pump defines the transmission ratio, corrected for the volumetric efficiency of those two members. Hydraulic continuously variable transmissions offer infinite transmission ratios starting from a zero ratio if the smallest displacement offered by the transmitting pump is zero. In that case, no clutch or torque converter is necessary. Furthermore, it is possible to provide several receiving hydraulic motor-pumps for a same transmitting hydraulic pump. However, hydraulic continuously variable transmissions accommodate high speeds of revolution poorly and have the drawback of having a low average output, said output varying greatly based on the speed and torque to be transmitted. For that reason, hydraulic continuously variable transmissions are generally provided on slow vehicles such as construction vehicles and agricultural machines, since they are compact and flexible, the transmitting pump and the receiving hydraulic motor(s) being able to be connected to each other by rigid or flexible ducts.
Whatever the type, the transmissions may optionally cooperate with one or more secondary energy storage means, i.e., energy previously converted into mechanical work by the heat engine of the vehicle. Said storage means make it possible on the one hand to operate said engine as close as possible to its optimal output, and on the other hand to recover part of the kinetic energy from the vehicle during its deceleration or braking, or part of the gravitational energy accumulated by said vehicle when it goes down a slope. Once stored, said secondary energy may be used later to reaccelerate said vehicle or to maintain its speed when it is in motion irrespective of the profile of the path on which it travels. Said secondary energy storage means may in particular consist of an electrochemicalor electrostatic electricity storage device, the latter then being reusable by an electric engine, a flywheel storing the kinetic energy recoverable via a mechanical transmission or via an electrical generator powering the electric engine, or a fluid or pressurized gas reservoir that can be used to drive a receiving hydraulic or pneumatic motor.
The energy capacity, output, power, and number of storage-recovery cycles that the different secondary energy storage means allow over their lifetime are the main characteristics that determine their relevance and interest. Furthermore, the durability of the storage offered by said means makes the latter more or less effective in reducing the energy consumption of motor vehicles based on the frequency and type of journeys they perform. The cost per kilowatt hour of stored energy and/or per kilowatt of power and the mass and volume energy density of said secondary energy storage means also make them more or less suitable for motor vehicle propulsion, which calls for widespread marketing of said storage means to significantly reduce their carbon dioxide emissions worldwide.
The secondary energy storage form most commonly used is electricity. This storage is used on vehicles called “heat-electric hybrids”, whether the latter are of the serial or parallel type, and irrespective of whether they are rechargeable. Electricity has the advantage of relatively high output over its entire production, storage and release chain, whether it involves the generator that produces said electricity from the mechanical work delivered by the heat engine or from the deceleration of the vehicle, the accumulators that store it, or the electric motor that converts it back into mechanical work. The electrochemical storage devices ordinarily used in this context can easily store the energy necessary for the vehicle to travel several kilometers, or even several tens of kilometers.
Used as secondary energy storage means, electricity nevertheless poses various problems, including the limited charge power of the electrochemical storage devices. The latter in fact only make it possible to store a limited fraction of the vehicle's kinetic energy during braking thereof, particularly regarding braking with a high deceleration. Another problem is that the lifetime of the storage devices is reduced to a limited number of charge-discharge cycles, whereas a very large number of braking operations are done over the lifetime of the motor vehicle. These two problems may be resolved through the use of electrostatic storage devices—also called “super capacitors”—but the latter are too expensive for wide scale use in the automotive field. Although they are more affordable, electrochemical storage devices nevertheless also remain expensive and require rare materials, while their manufacturing and recycling potentially pose various environmental problems. Furthermore, the higher the output of the electrical components of the propulsion system of a heat-electric hybrid motor vehicle is, the higher the cost to manufacture said components will be.
The use of a flywheel to store the secondary energy is known under the acronym “KERS” (Kinetic Energy Recovery System). These devices, primarily used in Formula I, are made up of a flywheel rotating at a high speed in a casing brought to a very low pressure, close to a vacuum. Said flywheel may temporarily be mechanically connected to the transmission of the vehicle using a continuously variable transmission, or indirectly using a generator and an electric motor. KER Shave the advantage of a high energy storage and recovery power, but on the other hand are expensive and potentially dangerous, generate unwanted gyroscopic effects, and only store the energy for a limited amount of time.
Secondary energy is stored using at least one pressure accumulator by various companies such as “Artemis Intelligent Power©”, “INNAS©”, “Bosch Rexroth©” and “Eaton©”, known for its “HLA®” (Hydraulic Launch Assist™) launch assist system, the latter two companies focusing particularly on applications for heavy vehicles or construction vehicles. The vehicles thus equipped are generally referred to as “hydraulic hybrids”, whether they are of the serial or parallel type. Upon request, the pressure accumulator used is connected either to a transmitting hydraulic motor-pump when the system is operating in storage mode, or to at least one receiving hydraulic motor-pump in recovery mode. Secondary energy storage using a pressure accumulator is difficult to apply to motor vehicles due to the high speeds of rotation of the heat engines used in those vehicles, said speeds being difficult to reconcile with the axial piston or radial piston hydraulic motor-pumps according to the state of the art, which are only capable of the necessary pressure and energy performance levels. Furthermore, the operating pressure of said motor-pumps remains relatively low, below 500 bar, which requires heavy and bulky pressure accumulators to store the secondary energy necessary for energy optimization of the vehicle, such accumulators being difficult to house in a private passenger vehicle.
In theory, however, the greatest reduction in fuel consumption is found through hydraulic hybridization due to its power, longevity and high storage-recovery output. In practice, when they are used to transmit mechanical work, hydraulic motor-pumps have a low output compared to that of involute gear pairs. Thus, the most common configuration is the parallel hydraulic hybrid, which comprises at least one hydraulic pump, a hydraulic motor-pump and hydraulic storage-recovery means alongside a conventional gear transmission. This type of configuration is generally found on heavy trucks operating at low speeds and making frequent stops and starts, such as garbage trucks and urban delivery trucks. However, it should be noted that the company “Peugeot-Citroen” has introduced a prototype thermal-hydraulic hybrid vehicle called “Hybrid Air” and based on the same architecture, i.e., with the parallel assembly of an automatic transmission and hydraulic braking energy storage-recovery pumps. The storage pressures remaining relatively low, the accumulators remain bulky and take up a large portion of the body understructure of the vehicle while only storing a very small quantity of energy. Despite this, the “Hybrid Air” concept has allowed “Peugeot-Citroën” to announce much lower fuel consumption levels compared to the state of the art.
In these fields of application, although internal or external gear pumps or vane pumps in particular exist, axial and radial piston hydraulic pumps offer the best output. Furthermore, it is possible to vary the displacement of these piston pumps, for example using a plate that may be more or less inclined, or a cage that may be more or less off-centered. To accommodate the continuously varying usage conditions of motor vehicles, said pumps must be able to operate under continuously variable speed, pressure and displacement conditions while preserving a high output which, in the current state of the state of the art, is not possible. In fact, according to the current state of the art, hydraulic piston pumps have an optimal output for a given speed, pressure and displacement. When one strays from these optimal operating conditions, the output of said pumps decreases rapidly, to the point that in the context of an automobile application, the benefit of the continuous gear ratio variation and of the recovery of the kinetic and gravitational energy of the vehicle is low or even zero, and even possibly negative.
The output of the hydraulic pumps is in particular determined by their sealing, which, being imperfect, implies the existence of leaks, for example at the pistons and the spool valve of said pumps. The output of the hydraulic pumps is also reduced on the one hand by the friction occurring in the contact zones between the moving parts and/or between the moving parts and the stationary parts making up said pumps, and on the other hand by the pressure losses occurring in the ducts of said pumps.
The use of hydraulic pumps suffers from various pitfalls and contradictions. A high pressure is favorable for the output of the hydraulic pumps, since it reduces the pressure losses thereof for a same duct definition. However, said high pressure reduces the volumetric efficiency of said pumps because not only are the leak flow rates of the latter increased for a same level of sealing, but said flow rates are higher relative to the flow rate of said pumps. Likewise, at isopressure, the more the displacement of a hydraulic pump is reduced to meet the instantaneous usage needs of a transmission, the greater its friction losses and sealing losses become relative to the work capacity transmitted by said pump.
However, producing a hydraulic transmission with secondary energy storage intended for automobiles encourages high pressures to favor the final output of said transmission as much as possible on the one hand, and to minimize the size of the secondary energy storage members on the other hand, whereas it is imperative in that context to have a hydraulic pump delivering a high output with low displacement, the vehicles most often being used at low speeds and low powers.
Furthermore, it will be noted that the need for high outputs remains, due in particular to the issues of controllability of the displacement of the various pumps and/or hydraulic motor-pumps used; issues of continuity of the power transmission, which must not be affected by the pulsations from the transmitting hydraulic pumps and the receiving hydraulic motor-pump(s); and the acoustic and cavitation erosion issues, the high operational pressures causing strong mechanical biases and potentially violent expansions of hydraulic fluid.
That is why it has been noted that hydraulic piston pumps have been subject to many developments to improve the functional and energy performance thereof. One of the most relevant embodiments is that by the company “Artemis Intelligent Power©”, which has produced a piston pump having excellent sealing levels and low friction losses due to rapid solenoid valves that regulate the hydraulic fluid intakes-outputs and the effective capacity of several pump cylinders placed radially around a cam ring. These solenoid valves and the electronic elements that control them makeup the “Digital Displacement©” concept, which advantageously replaces the typical mechanical spool valves, which generate non-negligible leaks and significant friction losses. Furthermore, the hydraulic pump by “Artemis Intelligent Power©” considerably limits the radial forces to which its pistons are subjected, which limits the associated energy losses thereof in the same proportions, said pistons operating in cylinders articulated in spherical chambers that cover the end thereof.
However, the pump by “Artemis Intelligent Power©” offers an even more pulsed operation when the displacement of said pump is low, the reduction of said displacement being done by truncating the working travel of the pistons. This is even more sensitive given that—for cost and bulk reasons—said pump can only include a limited number of cylinders, in particular in the context of a transmission for motor vehicle use. Whichever hypothesis is selected, the hydraulic pump by “Artemis Intelligent Power©” remains relatively expensive to manufacture, and the reliability and electricity consumption of its input/output solenoid valves biased upon each revolution remain crucial points.
Similarly, the company “INNAS©” has developed its “Floating Cup” concept, which results in a variable displacement piston pump with a high peak output and generating low pulses. This pump is in particular provided to propel a motor vehicle according to the “Hybrid” hydraulic hybridization concept claimed by that company. Although effective under certain usage conditions, the “Floating Cup” pump has many leak passages, and its volumetric efficiency is greatly decreased as a result, particularly with partial displacements. This is in contradiction with the specifications of a hydraulic pump intended to propel a motor vehicle.
Despite the issues described above and the challenges related to those issues, it would be a decisive advantage to have a fixed or variable displacement hydraulic motor-pump inexpensive enough to manufacture and with a high enough energy output for all industrial, household or automotive applications. Such a motor-pump would in particular make it possible to produce continuously variable hydraulic transmissions with braking energy recovery that are efficient, compact and cost-effective enough to be applicable to motor vehicles. Aside from being used to transmit the work produced by reciprocating internal combustion engines, such transmissions would make it possible to use non-reciprocating heat engines such as turbine engines, the latter requiring great flexibility in adjusting the instantaneous transmission ratio, power assistance upon starting the vehicle to offset the response time of said turbine engines, and recovery of the rotational kinetic energy of the turbines making up said turbine engines when they slow down or stop rotating.
In order to resolve the various problems related to hydraulic pumps and motors in general, and to manual or automated transmissions, automatic transmissions or continuously variable transmissions, irrespective of whether those transmissions are coupled to an electric, inertial or pressure accumulator secondary energy storage device, the fixed or variable displacement hydraulic motor-pump according to the invention offers, depending on the selected embodiment:                Compatibility with very high operating pressures, possibly up to two thousand bar or more, with low viscosity hydraulic fluids;        Complete reversibility, making it possible to use said hydraulic motor-pump indifferently as a hydraulic pump and as a hydraulic motor, with a similar output in “pump” mode and “motor” mode;        A high-output mechanical configuration in particular with hydraulic pistons that are not subject to any radial force, and with reaction of the majority of the forces by link bearings;        An input/output spool valve having low hydraulic leaks and friction losses;        Good continuous controllability of the displacement of said hydraulic motor-pump from a zero displacement to a maximal displacement;        Relative ease of providing a large number of pistons distributed angularly so as to limit the pressure and flow rate variations at the input or output of said hydraulic motor-pump;        Good compatibility with the relatively high speeds of rotation of automobile heat engines;        A moderate cost.        
In the specific context of the motor vehicle transmission, the fixed or variable displacement hydraulic motor-pump according to the invention provides:                A high hydraulic transmission output, close to that of manual transmissions with involute gear pairs, over an expanded speed and load range and compatible with all uses of a motor vehicle;        Vehicle take off from a stop without a clutch or torque converter, those two devices dissipating energy, with the possibility of a zero transmission ratio followed by infinite transmission ratios from that zero ratio up to a maximum transmission ratio;        A compact, powerful, robust, high-output secondary energy storage system, offering a number of storage-recovery cycles compatible with the entire lifetime of a motor vehicle, and capable of preserving a large majority of said secondary energy over long periods of time when said vehicle is stopped.        
As a result of these first features, the fixed or variable displacement hydraulic motor-pump according to the invention in particular makes it possible to:                Cause the heat engines, and in particular those used to propel motor vehicles, to work as close as possible to their best output, by continuously adapting the transmission ratio between said engines and the wheels of said automobiles;        Store all or part of the mechanical work produced by the heat engines that are used to propel the motor vehicles when said engines offer a high output, to then restore said work under driving conditions of said motor vehicles where it is preferable to avoid using said engines due to their excessively low output, said storage and release being done at a high output;        Recover a significant part of the kinetic energy of the motor vehicles during braking or deceleration thereof, and/or the gravitational energy of said vehicles when they descend slopes, then to release said energy in the form of mechanical work during the reacceleration of said vehicles, to propel said vehicles.        
Aside from these advantages, the fixed or variable displacement hydraulic motor-pump according to the invention provides, according to various embodiments, for:                Being able to load the reciprocating heat engines artificially upon cold engine start, i.e., to ask said engines for more power than necessary to propel the vehicle, that excess power on the one hand causing increased heat production at the exhaust of said engines, which accelerates the temperature increase of their pollutant post-treatment device, and on the other hand being converted into heat inside said engines to accelerate the temperature increase of the latter;        Performing the “stop and start” function, which provides for stopping the heat engines of motor vehicles when said vehicles are stopped, while offering a particularly rapid and powerful restart of said engines favoring the longevity of their hydrodynamic bearings, said “stop and start” function not—according to the invention—causing significant voltage drops in the power supply of said vehicles;        Propelling motor vehicles over distances of several meters or tens of meters without using their heat engine when the latter has been stopped using the “stop and start” function, this particularity reducing the number of restarts of said engine;        Assisting heat engines during motor vehicle takeoff from a stop, so as to offset the possible lack of torque of said engines due to their low displacement and/or high response time for their supercharging;        Facilitating the reduction of the displacement of motor vehicle heat engines—strategy intended to reduce the fuel consumption of said vehicles known by those skilled in the art under the term “downsizing”—in particular by simplifying the adaptation of supercharging of said engines, irrespective of whether that supercharging consists of one or more turbocharger(s) and/or mechanical compressor(s);        Assisting the heat engines during high power demands from the vehicles, so as to improve the performance of said vehicles;        Rotating one or more accessories installed on board motor vehicles, such as an air conditioning compressor, alternator, mechanical supercharging compressor, pump or any other member consuming mechanical work, with the heat engine running or stopped;        Filtering the torque variations at the output of the crankshaft of reciprocating internal combustion engines so as to reduce the sound and vibrational annoyances generated by said variations;        Assisting the rotation of the shaft connecting the turbine to the compressor of the turbocharger of the reciprocating internal combustion engines so as to accelerate the speed increase of said turbocharger in order to reduce the response time thereof;        Limiting the consequences of the response time of supercharging by the turbocharger of reciprocating internal combustion engines, by assisting the latter to propel vehicles when said supercharging does not allow said engines to deliver the desired torque in a short enough time, and by allowing said engines to increase their speed quickly to deliver the requested power and launch the turbine of said turbocharger.        
Thus, the fixed or variable displacement hydraulic motor-pump according to the invention makes it possible to:                Greatly reduce fuel consumption and polluting emissions from motor vehicles, particularly when they are used in urban settings, in particular by:                    Running their heat engines as close as possible to their best energy output or maximum power, irrespective of the driving conditions;            Accelerating heating upon cold start of their heat engine and their two-way or three-way catalytic converter so as on the one hand to reduce internal friction losses in the engine through rapid reduction of the viscosity of their lubricating oil, and on the other hand reduce the priming time for said catalytic converter;            Allowing, if necessary, regeneration of the particle filter under all circumstances and/or improving the operation of their selective catalytic reduction systems with the urea of nitrogen oxides, these devices most often being provided to control pollution from the exhaust gases of diesel engine vehicles;                        Increase the acceleration performance of motor vehicles without changing the heat engine or the mass or resistance to forward motion characteristics thereof, by allowing said engine—during said acceleration—to operate continuously at maximum power on the one hand, and not to undergo the transmission discontinuities specific to the manual or automatic transmissions on the other hand;        Make reducing the weight of motor vehicles less essential to increase the performance and/or reduce the fuel consumption thereof, the effect of said weight on said performance and consumption being lessened by the recovery of kinetic and gravitational energy and the possibility of running the heat engines at their optimal output or power, this making it possible—with equal dynamic and energy performance levels—to increase the level of comfort and safety equipment and/or reduce the price of the motor vehicles;        Increase the comfort of motor vehicle passengers by accelerating heating of the passenger compartment of said vehicles while making it possible to eliminate secondary heating devices for the passenger compartment as sometimes provided in diesel vehicles;        Greatly decrease the use of conventional motor vehicle friction brakes, which reduces the wear thereof as well as maintenance operations, with the corresponding reduction in maintenance costs and the particulate pollution created by said brakes;        Eliminate the additional electrical power necessary for the “stop & start” function ordinarily entrusted to an electric starter;        Replace the differential axle assembly of motor vehicles with means allowing dynamic control of the torque applied to each of the drive wheels of said vehicles.        
The fixed or variable displacement hydraulic motor-pump according to the invention further makes it possible, according to various embodiments, to:                Offer the drivers of any motor vehicle the choice between different control modes for the transmission of said vehicle, in particular to reproduce the driving conditions specific to the manual or automated, dual-clutch automatic, torque converter automatic, or continuously variable automatic transmissions, said drivers having infinite behaviors and steppings of the transmission ratios, preprogrammed or programmable, and able to be combined via any man-machine interfaces known by those skilled in the art, and said fixed or variable displacement hydraulic motor-pump according to the invention being controllable using any means—lever, vane, button or pedal—fixed or pluggable, interchangeable or retractable;        Give any motor vehicle an increased motor brake that can be adjusted to the liking of the driver so as to improve the driving comfort for said driver and save the brakes of the vehicle while reducing the risks of overheating of said brakes, so as to improve driver and passenger safety;        Impart a more dynamic nature to the heat engines by assisting them during their speed increases and braking them during their speed decreases.        
Furthermore, the fixed or variable displacement hydraulic motor-pump according to the invention allows the use of one or more turbines to propel the motor vehicles as an alternative to the reciprocating internal combustion engine, particularly according to the configuration described in French patent application no. FR 12 59827 dated Oct. 15, 2012 and belonging to the applicant. This combination of means is expected to drastically reduce the fuel consumption of motor vehicles and the carbon dioxide emissions resulting therefrom, which are low relative to the best references in this field. This combination is also expected to reduce the polluting, acoustic and vibratory emissions of said vehicles under particularly favorable economic conditions.
It is understood that aside from its application to motor vehicle transmission systems, the fixed or variable displacement hydraulic motor-pump according to the invention may be applied to many industrial and/or household fields.
The other features of the present invention have been described in the description and the secondary claims that depend directly or indirectly on the primary claim.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises:                At least one motor-pump central rotor that includes a central rotor power take-off and that is housed on or in a motor-pump frame, said rotor being able to rotate in at least one central rotor bearing comprised by said frame while remaining in as sealed contact as possible with at least one input/output spool valve kept approximately stationary relative to said frame, said spool valve being able to connect at least one hydraulic cylinder arranged radially or tangentially in said rotor with at least one internal input/output duct and at least one external input/output duct via an internal input/output central rotor channel and an input/output central rotor orifice arranged in the motor-pump central rotor, respectively, one of the ends of said ducts being secured directly or indirectly and sealably in the motor-pump frame, while the other end of said ducts is sealably secured in the input/output spool valve;        At least one hydraulic piston able to move in translation in the hydraulic cylinder and able to push a guided hydraulic piston plunger or able to be pushed by the latter, said plunger being guided in translation by a plunger guide arranged radially or tangentially in the motor-pump central rotor;        At least one tangential arm whereof one end is articulated in the motor-pump central rotor while the other end includes a tangential arm bearing face on plunger that can exert a force on a plunger path of contact on tangential arm included by the guided hydraulic piston plunger, the direction of said force being approximately tangential to the axis of rotation of said arm;        At least one motor-pump peripheral rotor made up of at least one cylindrical peripheral rotor casing whereof at least one end ends with a peripheral rotor flange, said peripheral rotor being able to rotate in at least one peripheral rotor bearing supported by a peripheral rotor stator that is directly or indirectly secured to the motor-pump frame, the motor-pump central rotor being completely or partially housed inside said peripheral rotor;        At least anti-friction means included by the tangential arm on its face situated opposite the tangential arm bearing face on plunger, said means bearing on the inner surface of the cylindrical peripheral rotor casing.        
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump peripheral rotor that is forced to rotate at the same speed as the motor-pump central rotor by an angular peripheral rotor synchro ring secured in rotation to a central rotor angular synchro ring included by the motor-pump central rotor by at least one angular synchronizing pinion rotating around at least one angular synchronizing pinion shaft comprised by the motor-pump frame.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises antifriction means that are made up of at least one tangential arm antifriction roller that can roll on the one hand on a tangential arm rolling track included by the tangential arm on its face situated opposite the tangential arm bearing face on plunger, and on the other hand on a peripheral rotor rolling track included by the inner surface of the peripheral rotor cylindrical casing, the travel of said roller being limited simultaneously relative to the tangential arm rolling track and the peripheral rotor rolling track by at least one tangential arm roller rack included by the tangential arm rolling track and by at least one peripheral rotor roller ring included by the peripheral roller rolling track, said rack and said ring simultaneously cooperating with at least one roller pinion included by said roller.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises antifriction means made up of at least one tangential arm friction pad included by the tangential arm on its face situated opposite the tangential arm bearing face on plunger, said pad being able to come into contact with a peripheral rotor friction track included by the inner surface of the peripheral rotor cylindrical casing.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a hydraulic piston that comprises a plunger ball joint on hydraulic piston on its circular face that is furthest from the motor-pump central rotor, said ball joint being made up of a hollow or raised truncated sphere shape that cooperates with a hydraulic piston ball joint on plunger comprised by the hydraulic piston guided plunger, said ball joint also being made up of a hollow or raised truncated sphere shape, while the two truncated sphere shapes are complementary and constitute a ball joint connection between said piston and said plunger.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a hydraulic piston guided plunger that comprises a brace placed in the extension of the hydraulic piston, and a strut mounted secured to said brace and perpendicular to the latter, said strut bearing the plunger path of contact on tangential arm, while each of its two ends can slide in the plunger guide.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump central rotor that includes a cylindrical axle housing in which a tangential arm axle is housed whereas the tangential arm is passed through by said axle so as to be articulated in the motor-pump central rotor.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump central rotor that includes a tangential arm return spring that bears on the one hand on said rotor and on the other hand on the tangential arm.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a peripheral rotor rolling track that includes at least one hollow or protruding guide rail that cooperates with at least one hollow or protruding guide groove included by the tangential arm antifriction roller.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a central rotor bearing that comprises an inner central rotor bearing track provided with at least one central rotor inner bearing ring, said track being secured to the motor-pump central rotor, on the one hand, and an outer central rotor bearing track provided with at least one central rotor outer bearing ring, said track being secured to the motor-pump frame, on the other hand, whereas at least three central rotor bearing rollers can simultaneously roll on the central rotor inner bearing track and on the central rotor outer bearing track and remain at a constant distance from each other owing to at least one roller pinion included by each central rotor bearing roller and which cooperates with said inner and outer rings.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a central rotor inner bearing track and/or a central rotor outer bearing track that includes at least one hollow or protruding guide rail that cooperates with at least one hollow or protruding guide groove included by the central rotor bearing rollers.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a peripheral rotor bearing that comprises a peripheral rotor inner bearing track provided with at least one peripheral rotor inner bearing ring, said track being secured to the motor-pump peripheral rotor, on the one hand, and a peripheral rotor outer bearing track provided with at least one peripheral rotor outer bearing ring, said track being secured to the peripheral rotor stator, on the other hand, whereas at least three peripheral rotor bearing rollers can roll simultaneously on the peripheral rotor inner bearing track and the peripheral rotor outer bearing track and remain at a constant distance from each other owing to at least one roller pinion included by each peripheral rotor bearing roller and which cooperates with said inner and outer rings.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a peripheral rotor inner bearing track and/or a peripheral rotor outer bearing track that includes at least one hollow or protruding guide rail that cooperates with at least one hollow protruding guide groove included by the peripheral rotor bearing rollers.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an input/output spool valve that is prevented from rotating with the motor-pump central rotor and is kept in rotation relative to the motor-pump frame by at least one lug or tie rod directly or indirectly fastened to the motor-pump frame.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an input/output spool valve that is a cylindrical stator housed with slight play in a stator cylinder arranged at the center of the motor-pump central rotor and coaxially to the latter, said stator containing an inner duct chamber that communicates on the one hand with the inner input/output duct, and on the other hand with an inner duct angular input/output manifold included by said stator in its periphery via an inner input/output spool valve channel, whereas said stator also contains an outer duct chamber that communicates on the one hand with the outer input/output duct, and on the other hand with an outer duct angular input/output manifold also included by said stator in its periphery via another inner input/output spool valve channel.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a cylindrical stator that includes, next to the inner duct input/output angular manifold, at least one outer duct radial force equalizing groove that communicates with the outer duct chamber via a spool valve equalizing inner channel whereas said stator also includes at least one inner duct radial force equalizing groove that communicates with the inner duct chamber via another spool valve equalizing inner channel, said groove being situated next to the outer duct angular input/output manifold.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a cylindrical stator that includes an axial sealing groove near at least one of its axial ends.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an input/output spool valve that is an axial stator made up of a distributing flange and an equalizing flange placed axially on either side of the motor-pump central rotor respectively across from a distribution face and an equalizing face formed on said rotor, said flanges being mechanically connected to each other via a central axial stator hub that axially passes through said central rotor via a stator cylinder arranged at the center of said central rotor and coaxially thereto, said stator containing an inner duct chamber that communicates on the one hand with the inner input/output duct, and on the other hand with an inner duct input/output angular manifold axially arranged on the inner face of the distributing flange via an inner spool valve input/output channel, whereas said stator also contains an outer duct chamber that communicates on the one hand with the outer input/output duct, and on the other hand with an outer duct input/output angular manifold also arranged axially on the inner face of the distributing flange via another inner spool valve input/output channel.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner duct chamber that communicates with an inner duct axial force equalizing groove arranged axially on the inner face of the equalizing flange via a spool valve equalizing inner channel, whereas the outer duct chamber communicates with an outer duct axial force equalizing groove also arranged axially on the inner face of the equalizing flange via another inner spool valve equalizing channel.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a distributing flange and/or an equalizing flange that includes a radial sealing groove at least at one of its radial ends.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an axial stator central hub that includes an axial sealing groove at least at one of its axial ends or at any point along its length.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises all or part of the inner duct input/output angular manifold, the outer duct input/output angular manifold, the outer duct radial force equalizing groove, the inner duct radial force equalizing groove, the axial sealing groove, the inner duct axial force equalizing groove, the outer duct axial force equalizing groove or the radial sealing groove, which is provided with a spool valve groove segment.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a spool valve groove segment that has at least one flank segment that laterally establishes sealing with the cylindrical stator or the axial stator, and at least one segment sealing line which on the one hand comes into contact with the motor-pump central rotor to form sealing, and which on the other hand is subjected to a force that tends to press it on said rotor due to the thrust exerted by a pressurized motor-pump oil contained by the cylindrical stator or the axial stator on the spool valve groove segment, said force being limited due to a small sprayed surface subjected to the pressure of said oil offered by said segment, which results from a segment force reacting shoulder included by said segment that cooperates with another shoulder arranged in the cylindrical stator or in the axial stator.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a spool valve groove segment that is kept in contact with the motor-pump central rotor by a segment groove bottom spring.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a spool valve groove segment that is made up of two half-segments that each have at least one segment flank kept in contact with the cylindrical stator or with the axial stator by a segment separating spring.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct that is secured in the input/output spool valve and/or in the motor-pump frame by one or the other of the ends of said duct using at least one fixed duct covering ball joint and/or at least one sliding duct covering ball joint, said ball joint having a covering ball joint step that may rest on a covering ball joint seat.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a fixed duct covering ball joint that is kept in contact with its covering ball joint seat by a covering ball joint spring that bears on the one hand on the input/output spool valve or on the motor-pump frame or on a sliding duct covering ball joint, and on the other hand directly or indirectly on said fixed covering ball joint.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a sliding duct covering ball joint that is made up of at least one sliding covering half-ball joint axially passed through by the inner input/output duct, said half-ball joint being able to translate axially and sealably relative to said inner duct, whereas said half-ball joint is kept in contact with its covering ball joint seat by a covering ball joint spring that bears on the one hand on the input/output spool valve or on the motor-pump frame or on another sliding covering half-ball joint, and on the other hand directly or indirectly on said sliding covering half-ball joint.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an outer input/output duct that is secured in the input/output spool valve and/or in the motor-pump frame by one or the other of the ends of said duct using at least one fixed duct covering ball joint, said ball joint having a covering ball joint step that can rest on a covering ball joint seat.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner duct chamber that is closed by an inner duct plug.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an outer duct chamber that is closed by an outer duct plug that is passed through by said outer input/output duct.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct that is housed completely or partially inside the outer input/output duct.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump frame that comprises a connecting satellite in which the inner input/output duct and/or the outer input/output duct are secured.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a peripheral rotor stator that is articulated on the angular synchronizing pinion axle, around which it can rotate under the action of a displacement varying servomotor.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a displacement varying servomotor that is a rotary electric servomotor motor that can rotate—in one direction or the other and by means of a servomotor reducing gear—a displacement-varying ring driving pinion, said pinion being able to rotate in a bearing arranged in the motor-pump frame and being able to rotate a displacement-varying ring secured to the peripheral rotor stator, the pitch circle of said ring being centered on the angular synchronizing pinion axle.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises rephasing means that are inserted between the peripheral rotor angular synchro ring and the central rotor angular synchro ring.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises rephasing means that are made up of at least one intermediate rephasing gear pair including at least one rephasing toothed wheel rotating around at least one rephasing axle secured to the peripheral rotor stator, said gear pair being inserted between the peripheral rotor angular synchro ring and the angular synchronizing pinion.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct and an outer input/output duct that are connected to the input or the output, respectively, of at least one second fixed or variable displacement hydraulic motor-pump, the fixed or variable displacement hydraulic motor-pump and the second fixed or variable displacement hydraulic motor-pump together making up a hydraulic transmission device.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a central rotor power take-off of the fixed or variable displacement motor-pump that is mechanically connected to at least one drive motor included by a motor vehicle, whereas the second fixed or variable displacement hydraulic motor-pump is mechanically connected to at least one driving wheel or track included by said vehicle, or vice versa.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct that can be connected with at least one high-pressure accumulator by at least one inner duct high-pressure accumulator valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an outer input/output duct that can be connected with at least one high-pressure accumulator by at least one outer duct high-pressure accumulator valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct that can be connected with at least one low-pressure accumulator by at least one inner duct low-pressure accumulator valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an outer input/output duct that can be connected with at least one low-pressure accumulator by at least one outer duct low-pressure accumulator valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a high-pressure accumulator and/or a low-pressure accumulator that comprises at least one accumulator separator piston able to move sealably in a blind accumulator cylinder, said piston delimiting, with said cylinder, a gas compartment containing a pressurized gas and oil compartment containing a motor-pump oil, the latter compartment being able to be connected with the inner input/output duct and/or the outer input/output duct.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an oil compartment that includes an accumulator-closing gate that the accumulator separator piston can press on an accumulator gate seat by pushing on a high-stiffness resisting spring inserted between said piston and said gate, so as to sealably isolate said compartment from the inner input/output duct and/or the outer input/output duct, said gate cooperating—unlike the high-stiffness resisting spring—with a low-stiffness resisting spring that tends to separate said gate from said seat.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an accumulator separator piston that can push on the high-stiffness resisting spring by means of a high-stiffness spring plunger that is guided in longitudinal translation by a gate and plunger guide secured to the high-pressure accumulator and/or the low-pressure accumulator, said gate guide also guiding the accumulator closing gate and including a plunger stop that determines the maximum travel of the high-stiffness spring plunger toward the accumulator separator piston.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a gate and plunger guide that includes at least one radial gate guide orifice that connects the oil compartment with the accumulator gate seat so as to allow the motor-pump oil to circulate between the inner input/output duct and/or the outer input/output duct and said oil compartment.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a high-pressure accumulator and/or a low-pressure accumulator that is connected to the inner input/output duct and/or the outer input/output duct by means of an accumulator locking valve that can sealably isolate said accumulator from said inner duct and/or said outer duct.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a low-pressure accumulator that is supplied with a motor-pump oil by at least one low-pressure pump driven by a low-pressure pump motor, the intake duct of said pump being connected to a motor-pump oil reservoir whereas its discharge duct is connected to said accumulator.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct that can be connected, by an inner duct exchanger-dissipater valve, with at least one exchanger-dissipater inner duct included by a pressure loss exchanger-dissipater, said duct comprising at least one outer dissipater heat exchange surface that is in contact with a coolant gas or a coolant liquid.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an outer input/output duct that can be connected, by an outer duct exchanger-dissipater valve, with at least one inner exchanger-dissipater duct included by a pressure loss exchanger-dissipater, said duct comprising at least one outer dissipater heat exchange surface that is in contact with a coolant gas or a coolant liquid.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an inner input/output duct that can be connected with a secondary hydraulic motor by an inner duct secondary motor valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises an outer input/output duct that can be connected with a secondary hydraulic motor by an outer duct secondary motor valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a secondary hydraulic motor that is made up of at least one hydraulic turbine mounted on a hydraulic turbine shaft that includes at least one hydraulic turbine blade on which at least one hydraulic turbine injector can axially and/or radially spray a jet of a motor-pump oil.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump management computer that controls the displacement-varying servomotor to control the displacement of the fixed or variable displacement hydraulic motor-pump, including that making up the hydraulic transmission device, irrespective of whether the latter is integrated into the motor vehicle, said computer also being able to command the inner duct high-pressure accumulator valve and/or the outer duct high-pressure accumulator valve and/or the inner duct low-pressure accumulator valve and/or the outer duct low-pressure accumulator valve and/or the accumulator locking valve and/or the low-pressure pump motor and/or the inner duct exchanger-dissipater valve and/or the outer duct exchanger-dissipater valve and/or the inner duct secondary motor valve and/or the outer duct secondary motor valve.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump management computer that is connected, by wired, lighted or electromagnetic information transmission means, to at least one shifting lever and/or at least one shifting vane and/or at least one shifting button and/or at least one clutch pedal and/or at least one brake pedal and/or at least one accelerator pedal included by a driving station comprised by the motor vehicle.
The fixed or variable displacement hydraulic motor-pump according to the present invention comprises a motor-pump management computer that is connected, by wired, lighted or electromagnetic information transmission means, to at least one transmission configuration button or knob and/or a transmission configuration screen and/or a transmission configuration microphone and/or a transmission configuration speaker included by a driving station comprised by said motor vehicle.